However, as Head of State, The Queen usually has to remain strictly neutral. This may not just apply to politics. We doubt the Queen will ever openly admit to showing favoritism toward any of her daughters-in-law.
It would appear unfair if she showed special treatment to one and not the other, so we suspect we will always be left wondering who truly is the favorite in-law of the Queen. All we do know is, the relationships in the royal family have strengthened in recent years, and we continue to see them grow and adapt as the Royal Family of Great Britain.